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(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)

(19) World Intellectual Property
Organization
International Bureau

(43) International Publication Date
13 May 2004 (13.05.2004)

PCT

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(10) International Publication Number

WO 2004/040285 A2

(51) International Patent Classification 7 :

G01N 27/00

(21) International Application Number:

PCT/GB2003/004667

(22) International Filing Date: 30 October 2003 (30.10.2003)

(25) Filing Language:

(26) Publication Language:

English

(30) Priority Data:

60/422,226
60/422,230
60/436,683
60/436,685

30 October 2002 (30.10.2002) US

27 December 2002 (27.12.2002) US

27 December 2002 (27. 1 2.2002) US

(71) Applicant (for all designated States except US): INVER-
NESS MEDICAL LIMITED [GB/GB]; Beechwood Park
North, Inverness IV2 3ED (GB).

(72) Inventor; and

(75) Inventor/Applicant (for US only): DAVIES, Obver,
William, Hardwicke f GB/GB] ; An Cluaran, Croy, Inver-
nesshire 1V2 5PG (GB).

(74) Agents: MERCER, Christopher, Paul et al.; Carpmaels
& Ransford, 43-45 Bloomsbury Square, London WC1A
2RA (GB).

(81) Designated States (national): AE, AG, AL, AM, AT, AU,
AZ,J3A, BB, BG, BR, B W, BY, BZ, CA, CH, CN, CO, CR,
CU, CZ, DE, DK, DM, DZ, EC, EE, EG, ES, FI, GB, GD,
GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, KE, KG, KP, KR,
KZ, LC, LK, LR, LS, LT, LU, LV, MA, MD, MG, MK, MN,
MW, MX, MZ, NI, NO, NZ, OM, PG, PH t PL, PT, RO, RU,
SC, SD, SE, SG, SK, SL, SY, TJ, TM, TN, TR, TT, TZ, UA,
UG, US, UZ, VC, VN, YU, ZA, ZM, Z W.

(84) Designated States (regional): ARIPO patent (B W, GH,
GM, KE, LS, MW, MZ, SD, SL, SZ, TZ, UG, ZM, ZW),
Eurasian patent (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM),
European patent (AT, BE, BG, CH, CY, CZ, DE, DK, EE,
ES, FI, FR, GB, GR, HU, IE, IT, LU, MC, NL, PT, RO, SE,
SI, SK, TR), OAPI patent (BF, BJ, CF, CG, CI, CM, GA,
GN, GQ, GW, ML, MR, NE, SN, TD, TG).

PuMished:

— without international search report and to be republished
upon receipt of that report

For two letter codes and other abbreviations, refer to the "Guid-
ance Notes on Codes and Abbreviations" appearing at the begin-
ning of each regular issue of the PCT Gazette.

<
IT)

(54) Title: PRECONDITIONING OF A SUBSTRATE IN A CONTINUOUS PROCESS FOR MANUFACTURE OF ELECTRO-
CHEMICAL SENSORS

(57) Abstract: The present invention described a method of preconditioning a substrate in a web manufacturing process wherein the
web manufacturing process includes a plurality of printing steps, the method comprising the steps of moving the substrate through
the web manufacturing process under tension; heating the substrate as the substrate is passed through the printing steps, wherein the
substrate temperature does not exceed a first predetermined temperature during the printing steps; and passing the substrate into a
preconditioning station wherein the substrate is heated to a second temperature which exceeds the first temperature.

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PRECONDITIONING OF A SUBSTRATE IN A CONTINUOUS PROCESS FOR
MANUFACTURE OF ELECTROCHEMICAL SENSORS

FIELD OF THE INVENTION

The present invention relates, in general, to an improved process for
manufacturing electrochemical sensors and, more particularly, to an improved web
manufacturing process wherein a substrate is preconditioned prior to printing
electrochemical sensor components.

BACKGROUND OF THE INVENTION

Electrochemical sensors are used in a variety of diagnostic procedures,
including the measurement of glucose in human blood. The manufacture of such
electrochemical sensors involves the manufacture of millions of small strips which each
include electrodes arranged in a sample receiving cell which is adapted to receive blood or
other bodily fluids. The bodily fluids the form complete circuit between the electrodes m
the cell. The electrodes are generally coated with at least one reagent that reacts with the
analyte (e.g. glucose) in the blood to form an intermediate analyte that may be measured by
a meter adapted to measure current or charge at the electrodes. Manufacture of such
electrochemical sensors requires the deposition of several layers of electrode material,
insulation material and reagent in a very small space and the accuracy and arrangements of
such layers is critical to the ultimate function of the device. Further, in order to hold down
eosts and meet demand, it is imperative that the electrochemical sensors be manufactured
at very high speeds and with absolute accuracy of alignment between the layers.

Electrochemical sensors can be used for many applications. In one application,
electrochemical sensor strip are inserted into specially adapted meters for self-monitoring
of glucose or other analytes (such as fructosamine, haematocrit etc) in, for example, blood
or interstitial fluid. Many analytes can be tested using such electrochemical sensors,
depending upon the design of the electrochemical sensor, the arrangement of the

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electrodes, the reagent used and other factors. Many of these applications, and in particular
strips for testing glucose, require sensor layouts of a particular size and construction, where
the manufacture is done within particular tolerances to render the electrochemical sensors
having characteristics which are as predictable and repeatable as possible.

The manufacturing process is further complicated by the need to manufacture
sensors many sensors very quickly where the sensors have very small cell sizes and,
therefore, very small electrodes within very tight tolerances. When testing blood or
interstitial fluid glucose, one of the main factors discouraging regular testing is the pain
involved in extracting the required amount of blood or interstitial fluid A larger volume
typically requires a greater amount of pain than a smaller volume. Thus, it is advantageous
to produce sensors that require a smaller amount of blood or interstitial fluid and therefore
are less painful to use, encouraging more regular discrete or continuous testing. One way
of requiring less analyte is to produce electrochemical sensor strips having a very small
structural features such as, very small sample receiving cells and very small electrodes
within those sample receiving cells, however, such small features more difficult to
manufacture, particularly in' an accurate and reproducible manner in order to produce
accurate and reproducible analyte measurements.

Many methods may be used to manufacture electrochemical sensors, including -
such processes as rotogravure and cylinder screen printing. In rotogravure printing a
cylinder is coated with a covering defining the shape of the feature (e.g. electrodes) to be
printed. Further cylinders may be used to print further films or layers (e.g. enzymes or
insulation layers).

Where an electrochemical sensor is fabricated by rotogravure printing of
electrically conductive ink to form one or more electrodes on a flexible web, which may be
polymeric. High quality print definition is possible using very thin inks. For the thicker
inks and greater print thicknesses required when printing electrochemical sensors fixed flat
screens have generally been used in single feed flat bed printing of electrochemical

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sensors. Other methods, including methods of manufacturing electrochemical sensors
using rotating printing structures have also been described.

In a web manufacturing process for electrochemical sensors, a web of substrate
ma terial ispassed through a series of print stations. At eachprint station, a new layer of
material such as, for example, electrode material, is deposited on the substrate or on a
previously deposited layer using, for example, a screon printing process. In the screen
printingprocess, the web is positioned under a screen and an ink, for example, a
conductive ink used to make electrodes is pushed through selected portions of the screen to
printalayerhavrngapredetermined layout on the portion of the web positioned below the
screen Thus, it is possible build the electrochemical sensor on the substrate by moving the
substrate from one print station to the next, printing each layer consecutively and cuttmg
the individual sensor's from the finished web.

In one manufacturing method an electrode layer and at least a first reagent layer
are manufactured by transporting a continuous web of the substrate past at least two pnnt
station, The print stations may be cylindrical rotogravure print stations or cylinder screen
print stations. However rotogravure (rotating an engraved cylinder) and cylinder screen
printing (rotating a cylindrical screen/stencil) methods of printing suffer drawbacks when
printing electrochemical sensors on a web. Rotogravure printing typically gives very dun
print heights. The thick electrically conductive inks needed to produce the required
electrode thickness for electrochemical sensors (especially those for blood glucose
detection) are particularly likely to suffer from incomplete, inconsistent printing with the
resultant reduction in electrochemical sensor quality, consistency and rehabihty.
Rotogravure printing with carbon inks (which typically have a high solid content and can
be quite viscous) for producing carbon electrodes is especially difficult as the solid/liquid
phases in the ink can separate resulting in incomplete or uneven filling or emptying of the
engravingfromprintto print. This can result in uneven print thicknesses and degradation
5 ofcarbon electrode quality and consistency. Cylinder screen printing is well suited to
single feed arrangements (as opposed to continuous web arrangements). Furthermore, the
ability to manipulate the way die screen interacts with the printing medium, and hence

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exert influence on the print quality by doing this) is limited because of the cylindrical
nature of the screen. Also, the variety of stencils available to achieve the correct ink
thickness for each type of ink (Carbon, silver/silver chloride, insulation, enzyme or other
reagent layer) is not readily commercially available.

Electrochemical sensors for testing blood or interstitial glucose may also be
produced in a multi step printing process using flat bed printers (such as Thieme or Svecia
available from Kippax UK, Huddersfield, UK and Registerprint, London, UK) and
metering an ink through screen stencils available from DEK Machinery, Weymouth, UK
and BTP Craftscreen, Coventry, UK) arranged parallel to the flat substrate cards to be
printed upon. This process has the advantage that the sensors can be produced in an
accurate repeatable manner so that a user can compare results from time to time. Sheets of
substrate for printing rows of strips thereon are passed through several flat bed printing
stages with the rows perpendicular to the direction of travel. In this manufacturing process
thin layers of ink are sequentially screen printed on to a polymeric substrate to form a large
group of sensor strips. Firstly carbon ink may be laid down to form an electrode layer. Next
an insulation ink layer may be laid down. Next a reagent layer, typically enzyme ink, may
be laid down. Next a second enzyme layer may be laid down. Next an adhesive layer may
be laid down. Finally, a hydrophilic layer may be laid down. A protective film may be
placed on top of the sensor sheet before prior to cutting the sheet into rows and the rows
into individual strips. A single sheet manufactured in this way of substrate may produce
500 or more sensor strips. These sensor strips are arranged in rows 0 to 9 perpendicular to
the direction of travel of the substrate sheet through the flat bed printer (the direction of
printing) with 50 sensor strips per row. Strips 1 to 50 in each row are each parallel to the
direction of printing. Each sheet may be manipulated by hand between each stage. In
particular following the four print steps (for printing carbon ink, insulation ink and two
layers of enzyme ink) each sheet may be manipulated by hand into a cutting machine so
that the cutting may be done along the rows separating one row of sensor strips from
another. Next each row may be manipulated so as to be cut into 50 separate strips. These
manipulation steps are time consuming and inefficient.

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Therefore there exists the need for an improved process for the manufacture of
electrochemical sensors, and in particular, for the manufacture of electrochemical sensors
for measurement of markers in the body such as in blood or interstitial fluid (glucose,
fructosamine, haematocrit and so on). There further exists aneed for a high speed,
predictable, reproducible way to manufacture sensor strips at a reasonable cost Further,
there exists a need for a high speed, predictable, reproducible way to manufacture sensor
strips having very small features where each finished strip may be used to reliably,
predictably and accurately measure analytes in bodily fluids in a reproducible manner.

In a continuous web manufacturing process for manufacturing electrochemical
sensors, the sensor substrate, which may also be referred to as the web, may expand or
stretch as it is heated up and placed under tension during the process. Each of the printing
stations in the manufacturing process (i.e. the print stations where the carbon, insulation,
and enzymes are deposited) may be followed by a drying station. In order to dry the inks
to dry efficiently, the drier stations operate at temperatures of, for example 50-140 degrees
centigrade. Furthermore to aid registration of the web through each printing station, the
web is placed under tension. The substrate has to be kept under tension to control
registration within the process, as a result, whenever the substrate is heated, for example to
dry the inks after printing, the substrate may stretch unpredictably causing image size
variation in subsequent prints.

The size of the image printed at each print station is determined by several
factors including stencil size, ink viscosity, relative web and stencil/screen speed and
substrate stretch at that point (both reversible and irreversible stretch). The image size
between different printing steps may also vary in unpredictable ways significantly reducing
yields. In one example, if the mismatch between image sizes between layers is greater than
300microns along the web the resulting sensor strip will not work and all of the strips in
that batch will have to be scrapped.

The excessive image size variation is believed to be due to excessive and
unpredictable stretching (due to heating and tension) and shrinking of the web substrate. It

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would, therefore, be advantageous to design a web process wherein the web or substrate
could be preconditioned to prevent unpredictable stretching during the manufacturing
process.

SUMMARY OF THE INVENTION

The present invention is directed to a method of preconditioning a substrate in a
web manufacturing process wherein the web manufacturing process includes a plurality of
printing steps. In one embodiment, the method of the present invention includes the steps
of moving the substrate through the web process under tension and heating the substrate as
the substrate is passed through the printing steps. In this invention, prior to any printing
steps, the substrate is passed through a preconditioning station which heats the substrate to
a predetermined temperature which meets or exceeds any temperature the substrate sees
during the remainder of the process. The temperature to which the substrate is heated
during the preconditioning process may be approximately 160°C. The preconditioning
station may also include at least one surface cleaning station adapted to remove impurities
from the substrate.

In order to improve printing in a method according to the present invention,
other steps may be included in the web manufacturing process. For example, the tension at
which the substrate may be stretched is sufficient to ensure that tension is not exceeded
during subsequent stages of the web process. Further, in one embodiment, predetermined
tension is approximately 1 65N and the second predetermined temperature is approximately
140°C. In a further embodiment of the present invention, in the preconditioning step, the
substrate is heated to a temperature sufficient to remove the irreversible stretch from the
substrate as it moves through the web process.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity in the
appended claims. A better understanding of the features and advantages of the present

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* a* following detailed description that sets forth
fflTistrative embodiments, in which the pruidpies
accompanying drawings of which:

^^^^^^^^^^
process.

a vtina a third fourth, and fifth sections of the web
Figure 2B is a schematic diagram depicting a third,

printing process.

Hpmrtine a sixth and seventh sections of the web printing
Figure 2C is a schematic diagram depicting a sixin

process.

^ktins a humid environment around a fifth and sixth
Figure 3 is a schematic diagram depicting a num

sections of the web printing,
of the web printing.

FigureSisaperspecfiveviewofapipewithperforations.

Figure 6 is a schematic diagram depicting a flood cycle

Figure 7 is a schematic diagram depicting a print cycle

Figure 8 is a schematic diagram depictmg2 different squeegee angles.

Figure 9 is a schematic diagram depicting 2 different squeegee positions.

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Figure 1 0 is a schematic diagram depicting a screen snap distance.
Figure 1 1 is an exploded view of a preconditioning zone (211).
Figure 12 is an exploded view of the first drying zone (217).
Figure 13 is an exploded view of a second drying zone (224).
Figure 14 is an exploded view of a third drying zone (230).
Figure 1 5 is an exploded view of a fourth drying zone (236).
Figure 16 is an exploded view of a first cleaning unit (204).

Figures 1 7A-1 7D are views of an insulation layer to carbon layer with proper registration.

Figures 18A-18D are views of an insulation layer to carbon layer with improper
registration when the artwork resulting from the screen 301 is stretched.

Figures 19A-19D are views of an insulation layer to carbon layer with improper
registration when the art work from screen 301 has not stretched'.

Figures 20A-20D are schematic diagrams depicting the print results for operator
registration of the web using a first view guide for visual inspection during an initial
registration process.

Figure 21 A is an example of a sensor sheet with a first and second web view guides; first,
second, third and fourth Y registration marks; and X registration marks.

Figure 21B is an exploded view of one row within a sensor sheet with a carbon X
registration mark.

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Figure 21 C is an exploded view of one row within a sensor sheet with an insulation X
registration mark over coating a carbon X registration mark.

Figure 22 is a schematic diagram of parameters X Y, and 9 used to register the web
printing process.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS OF THE

INVENTION

Figure 1 is a schematic diagram depicting 8 sections of the web printing process
according to the present invention. Section 1 is an nnwinder unit 101. Section 2 is a pre-
conditioning station 1 02. Section 3 is a carbon print station 103. Section 4 is an insulation
print station 104. Section 5 is a first enzyme print station 105. Section 6 is a second
enzymeprintstationioe. Section7isarewinderunit 107. Section 8 is a punch 108. It
will be understood by those skilled in the art that while the following description relates to
aprocess and apparatus concerning these 8 sections, the process and apparatus of the
invention can be embodied in greater or fewer numbers of sections. For example while 4
print stations are envisaged in this embodiment, one or more print stations couldbe used
without departing from the scope of the invention. In one embodiment there are a
minimum of two print stations for printing an electrode layer and a reagent layer.

In one embodiment of the present invention, Section 1 may be implemented
using a substrate material unwind unit 101 such as, for example, a Martin
Unwinder/Automatic Splice which is available from Martin Automatic Inc. in Rockford,
IL. In this embodiment of the invention, Sections 2, 3, 4, 5 and 6, maybe implemented
using a modified Kammann Printer, which is available from Werner Kammann
Mascbinefabrik Gmbh, model number 4.61 .35, in Biinde, Germany. In this embodiment
of the invention, Section 2 may be pre-conditioning unit 102. Pre-conditioning unit 102
may be used to precondition substrate 242 prior to printing and sections 3, 4, 5 and 6 may
be used to screen print carbon, insulation, first e D 2yme and second enzyme inks onto a
substrate 242. Section 7 may include rewinder unit 1 07 such as, for example, a Martin

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Rewinder, which is available from Martin Automatic Inc. in Rockford, IL. Section 8 may
include a punch 1 08 such as, for example, a Preco punch which is available from Preco
Press, in Lenexa, Kansas as model number 2024-P-40T XYT CCD CE. While specific
models of apparatus are mentioned, these pieces of apparatus may be varied and/or
replaced and/or omitted altogether without departing from the scope of the invention as
will be understood by those skilled in the art.

Figures 2A, 2B and 2C are schematic diagrams illustrating the path of substrate
242 as it passes through Sections 1-8 of a web printing process according to the present
invention. In one embodiment of the Invention, the material used for substrate 242 may be
a polyester material (trade name Melinex ® ST328), which is manufactured by DuPont
Teijin Films. Substrate 242 is supplied in a roll of material, which may be, for example,
nominally 350 microns thick by 370mm wide and approx. 660m in length. These
dimensions of thickness and width have been found to be particularly suitable for the
production of electrochemical sensors by flat screen printing on a web of substrate. This is
because of the requirement for the material to be robust for printing yet manipulable
through the apparatus and of sufficient width to accommodate a suitable quantity of sensors
to render the process commercially viable. Substrate 242 may include an acrylic coating
applied to one or both sides to improve ink adhesion. Polyester is a preferred material
because it behaves satisfactorily at elevated temperatures and tensions used during the web
process according to the present invention. While polyester and indeed Melinex are the
preferred materials in one embodiment of the invention, the use of other materials can be
envisaged by those skilled in the art from the description provided herein. Indeed, amongst
other things, variations in material thickness, width and length can be envisaged, a larger
width or length offering additional capacity for the production of sensors and a variation in
material thickness in some circumstances aiding the preconditioning, or registration during
printing. In a preferred embodiment of the present invention, prior to entering carbon
print station 1 03, substrate 242 is exposed to a heat stabilization process, by heating the
substrate up to 1 85 °C without placing it under significant tension to try and ensure that
substrate 242 experiences minimum dimensional distortion during the web printing process
where temperatures of between 140 and 160°C at tensions up to 1 65 N may be

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„ob though ft. beater. However, » »- *-* "* ^

,„ a temperature (typical., MV> r— *- "» » — — *"»

la , CTp[in «n gS .ap, to o M p re f^ OT ^t^»^^'»W™ d °^;°

oombmation of preconditioning «l phrcingunde, tension has greauy reduced tho
van^onsiopnn.regi^ti.oa^iotprovcdate^.pnKiuayteld. Inone

- * * f ° r — * ps "' spi,c °' 8

back Paper Tape ftom Intertapo Polymer Gtoop.

F i gore 2Aisa S cha™ t iodiag t am<i=pic 1 i„g S ec 1 io„l and section 2 of a w.b
printing process according .0 one entbodinren, of the pmaent invention In Ftgnre 2A
Ltion . is . unwinder nni. 101. Unwinder nni, ,0, inebrdes tint, arito, 200, **ond

^m«^-»-«-- - - m,B ' , ^ 2A, " dta "JT

mi ,207, 1 o».ee,l 208, tin, print nol,« 209, firs, drive ro„„ 2.0 and tint, —

b the embodiment of the invention illustiated in Fign* 2A, onvtinder unit 101
consists of, for example, a Martin UnwindCAn.omatio Sp.ice which is oaed ,o facrhtate
d,.o„ntinnonsmovem«o,.f S a,h S ti,,e242mtop^com.i«om„g S -m>mm,d«.

tension of approximate* SON. Unwmderum, .0. may include . hm.rmwmd admr 200

and a second unwind ad»r 20.. Note that an arbo, eon also be refened to .

Firs, mtwind omo, 200 holds a ,0,1 of substiat. materia, 242 and oontinoous.y feeds

s »b s ti,,o242i„,„ P re-oonditi„mngs,atio„,02of S oati„„2. Second urawind mbor 20,

bo,ds,s,^yro.lofsub^,,«242,wmohisan,»na«c,..,3plioed,ome^of,h«roo f

snbstiate 242 bom has, unwind arbor 200 ensuring a semi-continuous suppl, of substiat.

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242. This continuous process repeats from first unwind arbor 200 to second unwind arbor
201. A substrate material accumulator 203 stores a predetermined length of substrate 242
and dispenses the stored substrate 242 into pre-conditioning station 102 of section 2 while
the splicing operation takes place in first splice unit 202 (during which time both the first
unwind arbor 200 and second unwind arbor 201 are stationary). The splice created is a butt
splice with a length of splice tape on either side of the material at the joint In order to
ensure quality, approximately 10m of printed substrate maybe discarded either side of the
splice* First unwind aibor 200 and second unwind arbor 201 includes web edge guides
(not shown) which guide substrate 242 into first splice unit 202. The web edge guides are
adapted to prevent substrate 242 from wandering as it is being fed into first splice unit 202.

Typically the machine of the invention is set up to produce between 2 and 10
and more usually 6 rolls of substrate at any one time. For those print stations connected to a
continuous supply of ink, the number of rolls to be used is not usually a problem. However,
for the two enzyme print stations, to which a limited amount of ink is supplied, the number
of rolls to be used is an important input parameter. Indeed the number of rolls to be used
determines the amount of ink placed on the screen prior to start of the printing process. For
example for a 6 roll run, 6 (or rather just more than 6) rolls worth of enzyme ink are placed
on the screen prior to the start of printing in each of sections 5 and 6. Thus, the enzyme ink
needs to be kept in readiness for printing throughout the print run to ensure consistent
printing of enzyme over the whole life of the print run. A wall has been placed about the
screen in the enzyme print stations to ensure that a sufficient amount of enzyme ink can
be added to the screen without requiring the screen to be topped up during a run and also
reducing the risk of the enzyme ink overflowing the screen and onto the web substrate
running below it.)

In one embodiment of the present invention, substrate 242 is held under a
tension of approximately 165N throughout the process in order to maintain registration of
the four layers to be printed (typically the print registration tolerance is 300um). The
substrate 242 is also subjected to various temperatures of 140°C or less in order to dry the
printed inks during each printing step. Due to this tension and temperature, there may be a

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tendency for substrate 242 to stretch or expand during the process and consequently fell
outside the registration tolerance. Indeed the image size variation from print stage to pnnt
stage and print run to print run as well as within the print run itself was unpredictable and
higher than could be tolerated.

In the embodiment of the invention illustrated in Figure 2A, section 2 is a pre-
conditioning station 1 02. Pre-conditioning occurs before any image is printed onto the
substrate Substrate 242 is pre-conditioned to reduce the amount of expansion and stretch
within subsequent sections of the web process and also to aid the registration of substrate
242 through sections 3-6. Preconditioning station can heat substrate 242 to a temperature,
which is not exceeded in the subsequent print steps. Typically this takes place under
tension of between 150 and 180N more typically around 165N. However, in another
embodiment pre-conditioning station 102 can heat substrate 242 to a temperature suffice*
to remove the irreversible stretch from substrate 242, again optionally while under tensron
as described above.

In one embodiment of the invention, the substrate is heated to approximately
160°C in the preconditioning zone 211, which is illustrated in more detail in Figure 1 1 . As
explained above, in one embodiment of the present invention, the temperature to winch
substrate 242 is heated in pre-conditioning station 102 is not met or exceeded during
subsequent processing of substrate 242, including subsequent drying steps. Subsequent
print processes may compensate for the slightly larger image due to stretching caused by
the process of pre-conditioning station 102 by the provision of a slightly larger stencrl
screen size (typically 750pm in the direction of travel of the web). The provision of new
screens can be problematical. Other parameters can therefore be varied at each print staUon
to accommodate a variation in image size without replacing the screen, such as the relative
speed of the screen and the web. Nevertheless, there is a limit to the amount of image s.ze
variation that can be accommodated. It is therefore preferable to precondition the substrate
as described herein reducing the overall image size increase and reducing the variation m
said image size increase.

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In one embodiment of the present invention, pre-conditioning station 102 also
includes additional elements, which perform functions, which facilitate proper operation of
a web manufacturing process according to the present invention. In pre-conditioning unit
102, there are two web cleaning units, a first cleaning unit 204 and a second cleaning unit
207 which clean the top and underside of substrate 242. First cleaning unit 204 and second
cleaning unit 207 use tacky adhesive coated rollers to remove particulates from substrate
242 prior to any printing step. First cleaning unit 204 may be, for example, a cleaner
commercially available from KSM Web Cleaners, model number WASP400, in Glasgow,
United Kingdom. Second cleaning unit 207, for example, a cleaner commercially available
from Teknek. Pre-conditioning station 102 further includes inbound nip roller 206 and a
load cell 208. Inbound nip roller 206 is used to control the tension of substrate 242
(specifically the tension between inbound nip roller 206 and outbound nip roller 238).
Inbound nip roller 206 is linked via a control system (not shown) to load cell 208.
Substrate 242 is removed from second enzyme print station 106 in section 6 at a constant
rate by outbound nip roller 238. Load cell 208 in Section 2 measures the tension of
substrate 242 when it is moving through the web process according to the present
invention. Inbound nip roller 206 adjusts its speed in order to control the tension at a
predetermined set point. A typical substrate tension in a web manufacturing process
according to the present invention would be approximately 150N to 1 80N and more
specifically 160N to 170N, in this embodiment the tension is approximately! 65N.

Figure 2B is a schematic diagram depicting section 3, section 4 and section 5 of
a web printing process according to the present invention. In Figure 2B, section 3 is
carbon print station 103. Prior to printing (a cleaning system is installed (available from
Meech), which cleans the top side (print side) and underside of the substrate using a
vacuum and brush system, the top brush and vacuum station 251 and bottom brush and
vacuum station 250 are offset to one another. The top brush and vacuum station 250,
contacts the substrate immediately prior to the chilled roller 212 and accumulator 21 3 and
is the closest accessible point prior to carbon printing. The underside brush and vacuum
station 251, contacts the substrate immediately after the substrate exits the pre-conditioning
unit 1 02. Carbon print station 1 03 includes first chilled roller 2 1 2, second accumulator

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213, second print roller 214, first vision sensor 215, second drive roller 216, first drier zone
217 and second chilled roller 21 8. In the embodiment of the invention illustrated in Figure
2B, section 4 is insulation print station 104. Insulation print station 104 includes third
chilled roller 219, third accumulator 220, third print roller 221, second vision sensor 222,
first Y registration system (not shown) at position 237A, third drive roller 223 and second
drier zone 224. In Figure 2B, section 5 is first enzyme print station 105. First enzyme
print station 105 includes fourth chilled roller 225, fourth accumulator 226, fourth print
roller 227, third vision sensor 228, second Y registration system, at 237B (not shown),
fourth drive roller 229 and third drier zone 230.

In a process according to the present invention, section 3 of the web
manufacturing process is where carbon printing takes place. Of course, as will be
appreciated by those skilled in the art, the number and type of printing processes can be
varied without departing from the invention in its broadest context. For example, two
carbon prints may be provided or one or more prints with carbon with metallic particles,
silver/silver chloride ink or gold or palladium based inks may be used to provide an
electrode layer in the electrochemical sensors. The insulation and reagent layers may also
be varied in their composition, order of deposition, thickness of deposition and layout as
well as in other parameters apparent to those skilled in the art from the embodiments
described herein. In section 3, the carbon artwork for the electrochemical sensors
manufactured in accordance with the present invention may be printed utilizing screen-
printing. The basic components of the carbon print station 103 are illustrated in Figures 6
and 7. In particular, a suitable print station according to the present invention includes a
screen 301, lower print roller 303, print roller 600, a flood blade 603, a squeegee holder
605 and a squeegee 606. In carbon print station 103, print roller 600 is second print roller
214. Screen 301 is of generally flat construction and typically comprises a mesh arranged
to provide a negative of the artwork desired. Carbon ink is applied to the mesh and pushed
through it during printing. At this stage the flat screen may be deformed slightly out of a
flat shape by the weight of the ink (this is especially true for the enzyme print steps in
which all of the ink to be used during the entire print run is usually deposited on the screen

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at the start of the print run) and the pressure from the squeegee pushing the ink through the
mesh stencil.

In a flood cycle process in accordance with the present invention, screen 301 is
•charged with ink 604 by moving squeegee 606, flood blade 603, print roller 600, and lower
print roller 303, in first direction 608 which corresponds to the web movement of substrate
242. Screen 301 is moved in second direction 607 opposite to first direction 608 of
substrate 242 for the flood cycle where ink 604 is charged onto screen 301 ,

In a subsequent print cycle process in accordance with the present invention, as
illustrated in Figure 7, squeegee 606 transfers ink 604 through the screen 301 and onto
substrate 242. During the print cycle, the squeegee 606, flood blade 603, print roller 600,
and lower print roller 303 all move in second direction 607 which is opposite to the web
movement of substrate 242. Screen 301 is moved in first direction 608 which corresponds
to the web movement of substrate 242 for the print cycle where ink 604 is pushed through
screen 301 and deposited on substrate 242. Thus during the print cycle the screen 301
moves in the same direction as the web substrate at the same or very nearly the same speed
as the substrate. The screen 301 is substantially flat when at rest although in use it is
pushed by the squeegee 606 towards the web becoming slightly distorted as this happens
and substantially returning to it's original shape once the squeegee 606 is removed. The
screen 301 then moves in the opposite direction to the substrate as it is reloaded with ink
604 ready for the next print cycle. When the ink is loaded onto the screen 301 the weight
of the ink may ever so slightly bend the screen. The screen 301 is at an angle to the
direction of travel 608 of the web as it leaves the print station. This arrangement (the angle
being typically around 10 to 30 degrees and more specifically around 15 degrees)
improves ink release from the screen onto the substrate improving print definition and
reproducibility. The screen to substrate angle, squeegee angle, screen to squeegee distance,
squeegee to print roller position, snap distance, relative speeds of substrate and screen and
squeegee pressure can all be used to control and optimize the resultant print definition and
consistency across a card (One embodiment of a screen printing mechanism is described in
more detail in issued US patent 4,245,554 which is incorporated by reference herein.

,„„„. PCT/GB2003/004667
WO 2004/040285

In particular, in carbon print station 1 03, the ink in question is a carbon ink. An
exarnpleofasuitablecarboninkissetforthhereinbelow. In this embodiment of the
current invention, screen 301 is flooded with ink 604 prior to using squeegee 606 to
transfer the ink 604 through the screen and onto substrate 242. The printed carbon artwork
deposited on substrate 242 is then dried using, for example, hot air at 140«C directed onto
the printed surface of the substrate using four separate drying banks within the first drier
zone217, which is illustrated hi more detail in Figure 12.

Suitable ink for use in carbon print station include, but is not limited to, carbon with
metallic particles, silver/silver chloride, gold based, palladium based conductive printable
inks.

In one embodiment of the present invention, prior to the carbon printing process
and immediately after drying, substrate 242 is passed over a first chilled roller 21 2 which is
designed to rapidly cool substrate 242 to a predetermined temperature, typically room
temperature (around 18-21 °C and typically 19.5 °C +/- 0.5»C). In one embodiment of the
web manufacturingprocess according to the present invention the surface of first chilled
roller 212 is approximately 1 8<>C. First chilled roller 212 may be cooled to an appropriate
temperature using, for example, factory chilled water at around TC. The temperature of
the roller can be controlled by controlling the flow rate and/or the temperature of the
factory chilled water. After the printed carbon patterns are deposited in the printing
process, substrate 242 is passed over second chilled roller 218. Reducing the temperature
of substrate 242 andmamtaining the temperature of substrate 242 is beneficial because
cooler temperatures reduces the probability of ink drying on the screens during printing and
creating blocks in the mesh. The use of chilled rollers in a web manufacturing process
according to the present invention is also beneficial because it reduces the amount of
stretch in substrate 242, reducing registration problems and the need to modify the process
on the fly to compensate for such problems.

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In one embodiment, the temperature of the chilled rollers is controlled
dynamically by a feedback loop measuring the temperature of the chilled roller and
controlling the water flow/temperature. Other methods of chilling the rollers can be
envisaged by those skilled in the art from the embodiments described herein, for example,
electrically powered refrigeration units.

In a process according to the present invention, section 4 of the web
manufacturing process is where insulation printing takes place. In section 4, the insulation
artwork for the electrochemical sensors manufactured in accordance with the present
invention is printed utilizing screen-printing utilizing a generally flat screen. The basic
components of the insulation print station 1 04 are illustrated in Figures 6 and 7. In
particular, a suitable print station according to the present invention includes a screen 301,
lower print roller 303, print roller 600, a flood blade 603, a squeegee holder 605 and a
squeegee 606. In insulation print station 104, print roller 600 is third print roller 221 .

In a flood cycle process in accordance with the present invention, screen 301 is
charged with ink 604 by moving squeegee 606, flood blade 603, print roller 600, and lower
print roller 303, in first direction 608 which corresponds to the web movement of substrate
242. Screen 301 is moved in second direction 607 opposite to first direction 608 of
substrate 242 for the flood cycle where ink 604 is charged onto screen 301 .

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taxable flat sc^printag, during printtag. generally fiat screen hasa
™e».ofi,sreonon»l»eni S ^

^ as the,*** TypieaHyineaeJ.o. Sprint st anon3,« KS ub 9 «nMyfl 1 « S e K enu
ala naen.e»ngle(Ainfig™e6 1 «ofi 1 e S »b^e^«ae S aeena»<. S ubaWe n ovea»a,

of .heanbaMeanfi.hesce.varies.hesizenffi.e printed togen, the direerion of .revel
of the substrate, ie. the X-direction.

The stencil screen used in each of the print stations typically consists of a

^ienuydefonn^
embodiment apolye^e^

n.eshiscoatenvdthaUVsensinvecoatingandinconjunction^ a film posvnve the
screen is exposed to a UV light source, developed and dried so that the coating dries on the
screen to fonn a negative of the desired artwork hnage. With the aid of a squeegee, .nkrs
pa ,ed through theopenareasofthe stencil and onto the substrate (giving a posihve nnage
fonnedby theink on the substrate). The frame provides a means of mouuting the mesh
and withstanding the forces impost by the stretched mesh W im minimum distortaon and
with standing the additional forces produced during printing.

In particular, in insulation print station 104, the ink in question is an insulation
ink . Anexampleofasuitablemsulauoninkissetforthhereinbelow. In this embodiment
ofthe current invention, screen 301 is flooded with ink 604 prior to using squeegee 606 to
Wer ink604 through the screen and onto substrate 242. The printed insulation artwork

zone 224, which is illustrated in more detail in Figure 13. An example of a suitable mk for
use in insulationprint station in a web manufacturing process accordingto the present
invention is Ercon E6110-1 16 Jet Black Insulayer Ink which maybe purchased from
Ercon, Inc. In one embodiment ofthe invention, insulation artwork is registered to the
car bon artwork in the X direction (along the machine) and the Y direction (across the
m achine) utilizing the techniques described herein. Other types of insulation mk may be

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utilized as will be understood by those skilled in the art from the description herein.
Furthermore different layers or different orders of layers can be used to provide a different
order of layers and therefore different construction in the electrochemical sensors produced

In one embodiment of the present invention, before the insulation printing
process and immediately after drying, substrate 242, including printed carbon and
insulation patterns, is passed over third chilled roller 219 which is designed to rapidly cool
substrate 242 to a predetermined temperature typically room temperature (around 17-21 °C
and typically 19.5 °C +/- 0.5 °C). In one embodiment of the web manufacturing process
according to the present invention, the surface temperature of the third chilled roller is
approximately 18°C. Third chilled roller 219 may be cooled to an appropriate temperature
using, for example, factory chilled water at around 7°C. Reducing the temperature of
substrate 242 and maintaining the temperature of substrate 242 is beneficial because cooler
temperatures reduces the probability of ink drying on the screens and creating blocks in the
mesh. The use of chilled rollers in a web manufacturing process according to the present
invention is also beneficial because it reduces the amount of stretch in substrate 242,
reducing registration problems and the need to modify the process on the fly to compensate
for such problems.

In a process according to the present invention, section 5 of the web
manufacturing process is where the first enzyme printing takes place. In section 5, the
enzyme ink artwork for the electrochemical sensors manufactured in accordance with the
present invention is printed utilizing screen-printing and a movable generally flat screen as
herein before described. The basic components of the first enzyme print station 1 05 are
illustrated in Figures 6 and 7. In particular, a suitable print station according to the present
invention includes a screen 301 , lower print roller 303, print roller 600, a flood blade 603, a
squeegee holder 605 and a squeegee 606. In first enzyme print station 1 05, print roller 600
is fourth print roller 227.

In a flood cycle process in accordance with the present invention, screen 301 is
charged with ink 604 by moving squeegee 606, flood blade 603, print roller 600, and lower

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print roller 303, in first direction 608 which corresponds to the web movement of substrate
242. Screen 301 is moved in second direction 607 opposite to first direction 608 of
substrate 242 for the flood cycle where ink 604 is charged onto screen 301.

In particular, in first enzyme print station 105, the ink in question is an enzyme
ink. An example of a suitable enzyme ink is set forth herein below. In this embodiment
of the current invention, screen 301 is flooded with ink 604 prior to using squeegee 606 to
transfer the ink 604 through the screen and onto substrate 242. The printed enzyme
artwork deposited on substrate 242 is then dried using, for example, hot air at 50°C directed
onto the printed surface of the substrate using two separate drying banks within the third
drier zone230, which is illustrated in more detail in Figure 14. An example of a suitable
ink for use in first enzyme print station 105 in a web manufacturing process according to
the present invention as summarized in Table 2.

Table 2.

Glucose Oxidase Biozyme Laboratories

Tri-sodium Citrate Fisher Scientific

Citric Acid Fisher Scientific

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Poly Vinyl Alcohol Sigma Aldrich

Hydroxyethylcellulose (Nat 250 G) Honeywell and Stein

BDH/MerckLTD
Sigma- Aldrich Chemical Co., UK
Potassium hexacyanoferrate III Norlab Instruments Ltd., UK

DC1500Antifoam BDH/MerckLtd
Cabosil Ellis and Everard Ltd

PVPVA ISP Company Ltd

Analar Water BDH/Merck Ltd

In one embodiment of the present invention, after the insulation printing process
and immediately after drying, the substrate 242, including printed carbon and insulation
patterns, is passed over fourth chilled roller 225 which is designed to rapidly cool substrate
242 to a predetermined temperature typically room temperature (around 17-21 °C and
typically 1 9.5 °C +/- 0.5 °C).. In one embodiment of the web manufacturing process
according to the present invention the surface of fourth chilled roller 225 is approximately
1 8°C. Fourth chilled roller 225 may be cooled to an appropriate temperature using, for
example, factory chilled water at around 7°C. Reducing the temperature of substrate 242
and maintaining the temperature of substrate 242 is beneficial because cooler temperatures
reduces the probability of ink drying on the screens and creating blocks in the mesh. The
use of chilled rollers in a web manufacturing process according to the present invention is
also beneficial because it reduces the amount of stretch in substrate 242, reducing
registration problems and the need to modify the process on the fly to compensate for such
problems.

Additionally, due to the high water content of the enzyme ink and the airflow
due to the movement of the screen, it is crucial to ensure that the enzyme ink does not dry
into the screen. The relative flow of air encountered by the moving screen dries the ink on
the screen in a manner not normally observed in flat bed screen printers (such as Thieme
flat bed printers) since the screen itself does not move within the machine, unlike the
present invention. As well as the chilled roller alleviating this by ensuring the substrate is

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cooled to around 18°C before it encounters the enzyme screen-printing step, the screen
loaded with enzyme ink is humidified during printing. In one embodiment, humidification
is substantially continuous. Theremaybe topside, underside and/or side screen
humidification and indeed all three may be provided. An arrangement of pipes provides a
substantially constant stream of humidified air above, below and sideways onto the screen
respectively, ensuring the water content of the ink, is maintained at a constant level. A
suitable arrangement for providing topside, underside and/or side screen humidification
according to the present invention is illustrated in Figures 3, 4 and 5. The amount and
arrangement of humidification means (typically pipes carrying humidified air) will depend,
amongst other things, upon the amount of humidification required, the water content of the
ink, the humidity and temperature of the surrounding air, the temperature of the substrate
as it approaches the enzyme print station, the temperature of the print roller, the size of
the screen and the exposure of the screen to the surrounding (unhumidified air). In one
embodiment a pipe 304 comprising one or more rows of holes 400 delivers humidified air
across the whole underside of the screen during one stroke of the screenback and forth.
Pipes (not shown) above and to the operator side of the machine deliver humidified air
flows 300 and 304 (see figure 4).

Typically all the enzyme ink required for that print run is placed on the screen at
or prior to the start of the print run. Since the enzyme ink is composed of a large part of
water (typically between 55 and 65% by weight, more typically around 60 % by weight,
the ink is prone to drying out over the lifetime of the run. This risk can be alleviated by
providing humidification around the screen loaded with enzyme ink. Alternatively or more
typically in addition the substrate can be chilled prior to encountering the enzyme (or
indeed any) print stationby the use of chilled rollers as herein described. Typically the
temperature of the substrate is controlled to be less than or equal to the temperature of the
room. However, the temperature of the substrate is kept above the dew point for the
atmosphere in the room. If the room is at 60% humidity then the dew point maybe 15 °C.
If the temperature of the substrate falls below this then, condensation can occur on the
substrate potentially compromising any subsequent print run, especially any subsequent
print run with water soluble ink such as enzyme ink. Control of the substrate temperature,

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for example between the limits of room temperature and dew point, may therefore be
important for a successful print run. Control of temperature of and/or time passing over
chilled rollers 212, 219, 225, and 231 is important in controlling substrate temperature. A
feedback control loop can be used to measure the substrate temperature for example
relative to the room temperature and/or dew point (given the room's humidity) to control
the temperature of the chilled rollers and the temperature of the substrate as it leaves the
roller and approaches the next print station.

Figure 2C is a schematic diagram depicting section 6 and section 7 of a web
printing process according to the present invention. In Figure 2C, Section 6 is second
enzyme print station 1 06, Second enzyme print station 1 06 includes fifth chilled roller
23 1, fifth accumulator 232, fifth print roller 233, fourth vision sensor 234, fifth drive roller
235, fifth drier zone 236, Y registration system 237 and outbound nip roller 238. In the
embodiment of the invention illustrated in Figure 2C, section 7 is rewinder unit 1 07.
Rewinder unit 107 includes steering mechanism 239, first rewind arbor 240 and second
rewind arbor 241.

In a process according to the present invention, section 6 of the web
manufacturing process is where the second enzyme printing takes place. In section 6, the
enzyme ink artwork for the electrochemical sensors manufactured in accordance with the
present invention is printed utilizing screen-printing. The purpose of applying 2 coatings '
of the enzyme ink is to ensure complete coverage of the carbon electrodes and so that the
electrodes are substantially even and free of voids. The basic components of the second
enzyme print station 106 are illustrated in Figures 6 and 7. In particular, a suitable print
station according to the present invention includes a screen 301, lower print roller 303,
print roller 600, a flood blade 603, a squeegee holder 605 and a squeegee 606. In second
enzyme print station 1 06, print roller 600 is fifth print roller 23 3 .

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242. Screen 301 is moved in second direction 607 opposite to first direction 608 of
substrate 242 for the flood cycle where ink 604 is charged onto screen 301 .

hi particular, in second enzyme print station 106, the ink in question is an
enzyme ink. In this embodiment of the current invention, screen 301 is flooded with ink
604 prior to using squeegee 606 to transfer the ink 604 through the screen and onto
substrate 242. The printed enzyme artwork deposited on substrate 242 is then dried using,
for example, hot air at 50°C directed onto the printed surface of the substrate using two
separate drying banks within a fourth drier zone 236, which is illustrated in more detail in
Figure 15. An example of a suitable ink for use in second enzyme print station 106 is the
same as the enzyme ink used in first enzyme print station which is described in
aforementioned Table 2.

In one embodiment of the present invention, after the second enzyme printing
process and immediately after drying, the substrate 242, including printed carbon,
insulation, and enzyme ink patterns, is passed over fifth chilled roller 231 which is
designed to rapidly cool substrate 242 to a predetermined temperature. In one embodiment
of the web manufacturing process according to the present invention the surface of the fifth
Chilled roller 231 is approximately 18°C. Fifth chilled roller 23 1 maybe cooled to an
appropriate temperature using, for example, factory chilled water at around 7°C Reducing
the temperature of substrate 242 and maintaining the temperature of substrate 242 is

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beneficial because cooler temperatures reduces the probability of ink drying on the screens
and creating blocks in the mesh. The use of chilled rollers in a web manufacturing process
according to the present invention can also be beneficial because it reduces the amount of
stretch in substrate 242, reducing registration problems and the need to modify the process
on the fly to compensate for such problems.

Additionally, due to the high water content of the enzyme ink and the airflow
due to the movement of the screen, it is crucial to ensure that the enzyme ink does not dry
into the screen. As well as the chilled roller alleviating this by ensuring the substrate is
cooled to 18°C before it encounters the enzyme screen-printing step, there is also topside
and/or underside and/or side screen humidification, which can provide a stream of
humidified air above and below the screen , ensuring the water content of the ink is
maintained at a constant level. Typically the humidified air flows constantly over the
screen. A suitable arrangement for providing topside and underside screen humidification
according to the present invention is illustrated in Figure 3.

Second enzyme print station 106 may include outbound nip roller 238,
inspection system 237 for inspecting registration, third Y registration system at 237C (not
shown) and barcode station (not shown). Outbound nip roller 238 helps control the tension
of substrate 242 (specifically the tension between inbound nip roller 206 and outbound nip
roller 238). Substrate 242 is removed from second enzyme print station 106 at a constant
rate by outbound nip roller 238.. The Y registration system (not shown) at positons 237A,
237 B and 237C controls the Y registration (i.e. across the web) of each print cycle during
printing by utilizing the first Y registration marks 2101, second Y registration marks 2102,
third Y registration marks 2103, fourth Y registration marks 2104 which are illustrated in
Fig 21A. In one embodiment of the invention, first Y registration marks 2101, second Y
registration marks 2102, third Y registration marks 2103, and fourth Y registration marks
21 04 may correspond, respectively, to the Y registration of carbon print station 103,
insulation print station 104, first enzyme print station 105, and second enzyme print station
106. Each Y registration marks comprises 2 triangles that are juxtaposed in an orientation

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that approximates a rectangle. In one embodiment the Y registration system loeated at
positions 237A, 237B and 237C can be implemented by an EltromatDGC650 from
Eltromat Gmbh in Leopoldshohe, Gennany.

In one embodiment of the present invention, the inspection system 237, may be
hnplemented using the Eltromat Inspection System, model number PC3100 HD, which is
commercially available from Eltromat Gmbh in Leopoldshohe, Germany. The inspects
system237 has a vision component that inspects the registration marks illustrated in
Figures 1 7 A to 1 9D and/or figure 20D and can be used as a tool in assessing whether a
sensor sheet 21 06 should be rejected (for example by recording inspection results against a
barcode in a database).

Registration issues in the Y dimension (which canbe altered during printing by
the registration system (not'sho'wn) which is located at 237A, 237B and 237C and/or
inspected by inspection system 237 after all print stages are complete) may be ascribed to
variationsmwebtensionornoa-uniformdistor«onstothesubs«rate242. Inan

embodiment of the invention, the barcode station comprises the following commercally
avaUablecomponentsbarcodeprmter(modelnumberA400fromDominoUKLtd.ln

Cambridge, United Kingdom), barcode traverse system (Scottish Robotic Systems m
Permsinre, Scotland), and bar^ ^
barcode station (no shown) labels each row of the sensor sheet 21 06 with a 2 dimensronal
bar code. This provides eachrow of sensors a unique identifier code, batch/Lot number
identification, the sensor sheetnumber, and row number. The barcode station also reads
barcode immediately after printing to verify that the barcode has printed properly and
provides a visual indicator to the machine operators. The barcode and process informatmn
from sections 2 to 6 are stored in a database and used later to identify and subsequently
reject/accept cards for future process.

Rewinder unit 1 07 consists of, for example, a Martin Automatic Rewind
System. This is the last section of the machine and allows the continuous rewind of
substrate 242. Rewmder unit 107 consists of a first rewind arbor 240 and second rewind

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arbor 241 . First rewind arbor 240 holds a roll of substrate material 242 and continuously
pulls material from second enzyme print station 106. Second rewind arbor 241 holds a
standby roll of material, which automatically splices a first roll of substrate 242 into a
second roll on the completion of the roll of substrate 242 from first rewind arbor 240. This
continuous process repeats from first rewind arbor 240 to second rewind arbor 241. A
flying splice, which occurs while the substrate 242 is still moving, is used to enable the
continuous rewind of substrate 242. The splice is placed directly onto a fresh roll of
substrate material 242 which is primed with double sided pressure sensitive adhesive.

Figure 3 is a schematic diagram depicting the humid environment around a fifth
and sixth sections of the web printing. The basic components used to provide the means
for humidification of the web printing environment are illustrated in Figure 3 which
includes top humid air 300, screen 301 , bottom humid air 302, lower print roller 303, pipe
304 comprising multiple perforations 400, substrate 242, and either fourth print roller 227
or fifth print roller 233. Humidification and temperature is set to try and ensure that the
properties of the enzyme ink do not change to any significant extent over time during the
flood and print cycle and preferably over the life of the print run. in particular, it is
desirable that the viscosity and water content of the enzyme ink not change over time
during the flood and print cycle and preferably over the life of the print run.. The enzyme
ink is approximately 63% water. A constant water content ensures that the amount of ink
laid down onto the substrate 242 is consistent. If the water content of the ink changes
during the printing process, this can lead to variations in the enzyme layer thickness.
Additionally, loss of moisture from the enzyme ink shall lead to the enzyme drying on
screen 301 resulting in poor print definition and a reduction in the amount of ink laid onto
substrate 242. The humid air inside either first enzyme print station 1 05 or second enzyme
print station 106 is maintained between 85 to 95% relative humidity. Top humid air 300
and bottom humid air 302 is pumped onto both sides of screen 301 to maintain the desired
relative humidity. A side pipe 305 is arranged to one side of the web and introduces
humidified air to the web on one side immediately adjacent the enzyme print stations. The
nature and type of humidification arrangements can be varied to suit the size and shape of
the print station and the humidification requirements of that type of ink at that print station

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in that environment Oftenahood can be used to enclose the upper and/or lower side of the
screen so that humidified air can be delivered into the hood directly adjacent the screen and
retained within the vicinity of the screen by the presence of the hood. If the hood is
m ounted on theupper screen frame, as is typically the case, thehood may have a slot in the
x direction (the direction of printing) to allow the squeegee to move in relation to the
screen during the normal flood/print cycle.

Figure 4 is a bottom view depicting the humid environment around a fifth and
sixth sections of the web printing. The basic components used to provide the means for
humidification of the web printing environment are also illustrated in Figure 4 which
includes top humid air 300, screen 301 .bottom humid air 302, pipe with perforations 304,
and perforations 400, side pipe at 305 (not shown). A pipe 304 with several perforations
400 is positioned underneath screen 301 as a means for blowing bottom humid air 302 to
maintain the viscosity of the enzyme ink on screen 301 . Figure 5 is a perspective view of
pipe 304 with perforations 400 to blow bottom humid air 302.

Figure 8 is a schematic diagram depicting 2 different squeegee angles which
includes a substrate 242, print roller 600, and squeegee 606. The angle of the squeegee 800
can be varied to optimize the definition of the print area. In an embodiment of the
m ventionmeangleofmesqueegeec^bel5 + /-5andpreferably + /-lto2 degrees. Note

that the contact point of the squeegee 606 to print roller 600 is the same for every squeegee

angle 800.

Figure 9 is a schematic diagram depicting 2 different squeegee positions which
includes substrate 242, print roller 600, lower print roller 303, squeegee 606, first squeegee
position 900, and second squeegee position 901. The squeegee position is the position of
the squeegee relative to the center of the print roller 600. The squeegee position can have a
major effect on the thickness of printed ink. The position of the squeegee can be varied to
optimize the definition of the print area.

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Figure 1 0 is a schematic diagram depicting a screen snap distance (1 000) which
includes substrate 242, print roller 600, lower print roller 303, and screen 301; In one
embodiment of the invention, screen snap distance (1000) is the closest distance between
screen 301 and substrate 242. In a prefeired embodiment of this invention, screen snap
setting (1000) may be approximately 0.7mm. If the screen snap setting (1000) is set too
high, squeegee 606 cannot sufficiently deflect screen 301 to transfer ink 604 onto substrate
242 with sufficient print definition. If the screen snap setting (1000) is set too low, screen
301 will smear ink 604 from a previous print cycle causing insufficient print definition.

Figure 1 1 illustrates an exploded view of a preconditioning zone 211 which
comprises first drive roller 2 1 0, hot plate 1 1 00, first heater bank 1 101 , second heater bank
1 102, and third heater bank 1 1 03. In an embodiment of the invention, hot plate 1 1 00
contacts the unprinted side of substrate 242. In a preferred embodiment of this invention,
hot plate 1 1 00 may be coated with Teflon and may be heated to approximately 1 60°C. In
an embodiment of the invention, first heater bank 1 101, second heater bank 1 102, and third
heater bank 1 1 03 blow hot air at approximately 1 60°C. This may be varied to suit the
substrate type and/or thickness and/or any pretreatment and/or later temperatures
encountered in the process as would be understood by those skilled in the art.

Figure 12 illustrates an exploded view of a first drying zone 217 which
comprises second chilled roller 2 1 8, second drive roller 2 1 6, first drier bank 1 200A, second
drier bank 1 101 A, third drier bank 11 02A, and fourth drier bank 11 03 A. In an
embodiment of the invention, first drier bank 1200A, second drier bank 1 101 A, third drier
bank 1 102A, and fourth drier bank 1 103 A blow hot air at approximately 140°C although
this may be varied as would be understood by those skilled in the art from the description
herein.

Figure 1 3 illustrates an exploded view of a second drying zone 224 which
comprises third drive roller 223, first drier bank 1200B, second drier bank 1 101B, third
drier bank 11 02B, and fourth drier bank 1103 B. In an embodiment of the invention, first
drier bank 1200B, second drier bank 1 101B, third drier bank 1 102B, and fourth drier bank

PCT/GB2003/004667

WO 2004/040285

md e^ bj 0^ i° the art tan descnption herem.

Hffire 14 ilh.stra.es » exploded view of a third drying zone 230 which
c^fonrthdriveroUer 229,ta. drierbank , 2M C, and second drier benknOlC. In
. embodimen. of the invention M drier bank f20»C and seoond dne, bank >W
Mow, ho. air «. *fC altbongh this may be varied as wonld be ooderstood

by those skilled in die art tan die description herein.

Figmel5ilb^es.nexplod«dviewofa fonrth .hying zone 236 which
c^prisesttihdriven^.Wdrierb- ,2C»D, and second drie, ban, '•"'">• to

mm ho. air a. approximately 50'C althoogh dns »>a, be varied as womd be nnd^ood
by those skilled in Ihe art horn die description herein.

Figure .6 iliusnates an exploded view of a fa. cl«mngonit 204 which

M b,»« poller rodees ,60! con.ao. Ore .op and bodom s,de of snbrtrate 242 and
Wen, particnlaWforeign material to tacky rollm 1600.

Hgrnns.7Atol7Dillns.mte views of anh^onlnytftocaabonlayespnn.
foim end»diMen.„fdaotovenrionwid, P ™per,egis M doa Note that Figure 17 A
— toe.oplog.Figme.TB^toprighkFigtn.nCd.ebonomleftondBgnre

M in hgo,. 2. A In one embodiment of mis invention, carbon pnn. s ahon .03
prints caabon layer whichcomprisesasolid carbon re ctongle HOOamron. =db,n
mobmgma, camo. line .20, onto snbsbate 242. In a snbsermen, prim cycle msnladon
print stori„„lMprin B r«.a»g..»insm»don,toe.70 1 on,.s„bstoate242whteb»

,703 ^to.ta.adonlsy.rtotanbonl.yorregisW.ionispropesa.al.fom.om..
typify theremaybe no oncoa.ed snbsteate 242 showi.gb.awee, toe r.ctangola,

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insulating line 1701 and solid carbon rectangle 1700. The registration of insulation layer to
carbon layer can be checked manually by an operator or can be checked using second
vision sensor 222, which in one embodiment comprises a camera pointed at each corner of
the substrate. Typically this forms part of the initialization at the start of the print run. An
operator can view all four corners of the substrate adjacent one another on a TV screen.
The operator can then visually inspect the registration of insulation to caibon during this
initialization process (and indeed during the remainder of the print run) and can make
whatever adjustments are necessary to bring the insulation and carbon prints into
registration. It should be appreciated that the web viewer 222 (comprising , for example, 4
cameras pointed at locations above four corner of the substrate card) views and forwards
for display a snapshot of each of the four corners of each card. Thus the corners of each
card are only viewed for a fraction of a second on the display since the substrate beneath
the viewing cameras is constantly being replaced as the web travels through the apparatus.
This system enables an operator to see instantly the effects any adjustment he may make*
has on the insulation to carbon registration. Adjustments the operator may make include,
but are not limited to, screen print stroke, snap height, squeegee pressure, screen position
relative to tf Y" direction, screen position in relation to 9 (Theta). Once the viewer
registration has been set up on this and other print stations (using viewers 228 and 234) the
automatic internal X registration system (using marks 2107 and 2108) and the automatic Y
registration system (for example, registration systems located at positions 237A, 237B and
237C using marks 2101 to 2104) are allowed to take over and monitor and automatically
coirect X and Y registration during printing. Marks 1700 to 1703 shown in figures 17A to
20 D can be used for automatic X and Y registration during printing as an alternative or in
addition to using marks 2101 to 2104 and 2107 and 2108 as would be understood by those
skilled in the art from the description herein.

Figure 1 8 illustrates a view of an insulation layer to carbon layer for an
embodiment of the invention with improper registration when the insulation artwork is
longer in the direction of printing than the carbon artwork. This may occur even if the
carbon and insulation screen are the same size in this dimension because of the substrate
may have stretched or the screen stroke may be different in each stage (a slower screen

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stroke

bottom left, andFigarelSDAebottomright of sensor **2106. When the insulation
.ayertocarbonlayerregistrationisimproper at oneofthe four comers uncoated substrate
2 42canbeob S ervedbetweenmerectan^^

rectangle 1700. The registration of insulation layer to carbon layer can be checked
manually by an operator using second vision sensor 222.

Figure 19 illustrates a view of an insulation layer to carbon layer for an
embodiment of the invention with improper registration when the printed insulation
artwork is shorter than that of the carbon print (for example, the screen stroke for the
insulation print may be longer than thatofthe carbon, or the insulation screen may be
shorter than that of the carbon print station) Note mat Figure 19A represents the top left,
Figure 19B the top right, Figure 19C thebottom left, and Figure 19D the bottom right of
sensor sheet 2 1 06. When the insulation layer to carbon layer registration is ^proper at
one of the four comers uncoated substrate 242 can be observed between the rectangular
insulating line!701 and solid carbon rectangle 1700. The registration of insulation layer to
carbon layer can be checked manually by an operator using second vision sensor 222.
Figures 20A to 20 D are schematic diagrams depicting the results of a process for pruning
a second view guide 2002 (see Figure 21 A) which comprises solid carbon rectangle 1700,
hollow insulation rectangular line 1701,hollow carbon rectangle 1703, solid rectangle from
the first enzyme layer 2000, solid rectangle from the second enzyme layer 2001 , and
uncoated substrate 242. Optionally, such prints ean also be used during manufacture by
automatic ongoing inspection systems such as inspection system 237 in section 6 (after the
second enzyme print). Ongoing registration is typically otherwise carried out by a
registration system (not shown) at positions 237A, 237B and 237C in the «Y» direction
and bya registration control system looking at marks 2105 (see figure21A)in the "X"
direction).

Figure 21 A is an example of a sensor sheet with a first view guide 2100 and
second view guide 2002; first Y registration marks 21 01 , second Y registration marks

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2102, third Y registration marks 2103, and fourth Y registration marks 2104; and X
registration marks 2105. Note that X registration marks 2105 comprises carbon X
registration mark 2107 and insulation X registration mark 2108. Figure 21B is an exploded
view of one row within sensor sheet 2106 with a carbon X registration mark 21 07 and
second view guide 2002. Figure 21 C is an exploded, view of one row within sensor sheet
21 06 with an insulation X registration mark 2 1 08 and second view guide 2002. Insulation
X mark 2108 entirely overcoats carbon X registration mark 2107 as illustrated in Figure
21 C and in doing so provides a trigger point (left hand edge say of mark 21 08) in advance
of that of the original carbon mark 2107. This means that any subsequent layers are printed
in relation to, the second printed layer (in this case the insulation layer) rather than the
carbon layer. This can be useful say if the second and subsequent screen artwork
dimensions are longer in the X direction (along the web) than the first screen artwork
dimension in the X direction.

An exploded view of one corner of the print guides is shown in Figure 20A-D,
in the sequence in which they are printed. At section 3 of carbon print station 103, a solid
carbon rectangle 1 700 is printed along with a rectangular carbon line 1 703, which
surrounds the solid carbon rectangle 1700. At section 4 of insulation print station 104, a
rectangular insulation line 1701 is printed between the solid carbon rectangle 1 700 and the
rectangular carbon line 1703. When insulation to carbon registration is correct at all four
comers typically there will be no uncoated substrate 242 showing between solid carbon
rectangle 1 700 and rectangular insulating line 1 701 . Additionally, at section 4 of insulation
print station 1 04, there are two more rectangular insulation lines 1 701 printed directly
above the solid carbon rectangle 1700. These two additional insulation lines are used to
visually assess the registration of first enzyme layer 2000 to the insulation layer and second
enzyme layer 2001 to the insulation layer, this is done so by printing a solid rectangle of
enzyme ink within the rectangular insulation line as illustrated in Figure 20C and 20D.
Thus the third and fourth printed layers can be registered to the second and not to the first
printed layers. This has the advantage that a change in artwork size between the first and
second layers (which may be required should the substrate stretch after the first print
station for example due to the heat and tension encountered in the first drying zone 21 7)

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can be accommodated without adverse effect on print registration (a tolerance of 300pm is
typical in the X direction).

As illustrated in Figures 1 and 2, at the end of the process, substrate 242,
including** sensors printed thereon is rewound by rewinder unit 107 and is then fed into
punchlOS, which may be, for example, a Preco punch which is located withinalow
humidity environment. The Preco Punch is a CCD X, Y, Theta, Floating Bolster Punch.
The Preco Punch registration system uses a CCD vision system to look at "Preco Dots"
which are printed on the Carbon print station, these allow the punch to adjust to the carbon
print and enable the punch to "pouch" the cards out square. The output of Punch 108 is a
set of punched cards such as those illustrated in Figure 21 A. Punched cards are ejected
from punch 1 08 onto a conveyer belt, this conveyer belt transports the cards under a
barcode reader which reads two of the barcodes on each card to identify whether the card »
accept or reject in relation to the Web Database. Automatic or manual extraction of
rejected cards can carried out The cards are then stacked on top of one another in
preparation for the next manufacturing step.

At carbon print station 103, insulation print station 104, first enzyme print
station 1 05, and second enzyme print station 1 06 all have a means for visually inspecting
the registration immediately after the printing process step using first vision sensor 215,
second vision sensor 222, third vision sensor 228, fourth vision sensor 234, respectively.
For each section in the web printing manufacturing process - Section 3, 4, 5 and 6 - there
are Web Viewer camera systems located immediately after the printing process step. See
Figure's 2A-2C for web viewer locations. There are two cameras at Section 3 and four
cameras each at Section 4, 5 and 6. The web viewer cameras are part of a manual set-up
process used by the Web machine operators during the start of the print run. The cameras
are used to view printed marks, which aid the initial set-up of carbon alignment to substrate
242 and registration between insulation layer to carbon layer, first enzyme layer to
insulation layer, and second enzyme layer to insulation layer. The printing guides are
" illustrated indicated on Figure 21A. For carbon print alignment, second view guide 2100 »
used to indicate the carbon print position in relation to the edge of substrate 242 as it runs

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through carbon print station 103. There is a leading line and a trailing line as illustrated in
Figure 21 A. The carbon print is adjusted until the lines indicate that the print is square to
the substrate edge. Registration of the individually printed layers is required in the X
direction (along the length of the machine) and the Y direction (across the width of the
machine) See Figure 2 1 A. X direction registration is controlled by the internal registration
system of the machine. This utilizes the printed areas indicated on Figure 21 A, B and C.
On the Carbon print, cycle a carbon X registration mark 2107 is printed in this area. The
Insulation printing cycle is registered to the Carbon print using sensors which use carbon X
registration mark 2107 to allow the insulation screen to adjust in order to print the
insulation ink in the correct position. The carbon X registration mark 21 07 used for this
1 purpose is then over printed with insulation X registration mark 21 08 and is utilized in the
same manner to correctly register first enzyme layer 2000 and second enzyme layer 2001
with the insulation print. Y direction registration is controlled by Y registration system
(not shown) located at positons 23 7A, 237B and 237C which in one embodiment of the
invention may be an Eltrornat registration system, model number DGC650 from
Leopoldshohe, Germany. This utilizes the printed areas 2101 to 2104 indicated in Figure
21 A. On each print cycle - Carbon, Insulation, Enzymel and Enzyme2 - these marks are
printed in order that the subsequent print is registered, via sensors, in the Y direction. The
Web Database records process information during printing. Information recorded in the
database can be traced back to each individual card via a barcode, in one embodiment a 2D
barcode is used. Typical information gathered in the Web database is outlined in Table 3.
The Web Database has the ability to assess whether a process parameter is Acceptable or

Unacceptable and can be used to reject cards on this basis - whether the parameters were
running within there tolerance limit. Unacceptable cards may be removed at future
processes either manually or automatically.

Table 3.

Hot Plate 1 of

Drier Bank 1

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Drier Bank 2
ofl

Drier Bank 3
ofl

Drier Bank 4
ofl

of2

Drier Bank 2
of2

Drier Bank 3
of2

Drier Bank 4
of 2

Squeegee
Pressure

of3

Drier Bank 2
of 3

Drier Bank 3
of3

Drier Bank 4
of3

Squeegee
Pressure

of4

Drier Bank 2
of4

Squeegee
Pressure

Inside Hood
%RH

Inside Hood
Temp

Outside
Hood %RH

of4

Drier Bank 2
of4

Squeegee
Pressure

Inside Hood
%RH

Inside Hood
Temp

Outside
Hood %RH

Outside
Hood Temp

Web Tension

Web Speed

Figure 22 is a schematic diagram of parameters X, Y, Z, and 9 used to register
the web printing process. The parameter Y represents the direction from the operator to the
machine side of the web printing machine (typically horizontal). The parameter X
represents the direction from unwind unit 101 to rewinder unit 107 (typically horizontal).
The parameter Z represents the direction perpendicular to the X and Y directions (typically
vertical). The parameter 9 represents the angle around the Z axis. In an embodiment of this
invention, the following parameters are used to register the following print process such as,
for example, carbon print station 103, insulation print station 104, first enzyme print station
1 05, and second enzyme print station 106.

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In one embodiment of the present invention, the output of the web
manufacturing process is cards printed with artwork comprising Carbon, Insulation and
two identical Enzyme layers printed in register with one another to form strips each
containing an electrochemical sensor and associated contact electrodes for detecting
Glucose in a blood sample. The strips are used for self-monitoring of blood glucose in
conjunction with a meter. Productions of several designs of strips are envisaged. At present
the web is designed to produce "One Touch Ultra" strips for use in the One Touch Ultra
meter which is available from LifeScan, Inc.

A schematic diagram sample of the artwork produced is in Figure 21 A. This
illustrates one complete printed card, which contains 10 "Rows" of 50 "Strips". There are a
total of 500 "Strips" per card. Print orientations are also indicated. By printing rows 0 to 9
(each of 50 strips) parallel to the direction of print, the process can be easily extended to
inclusion of a cutting step separating one row from another. Furthermore this means that
any defective rows resulting from cross web variation in print quality (perpendicular to the
direction of print)can be identified easily. Each row is allocated a number^identifled by a
barcode) and therefore specific rows from specific sheets on the web can later be identified
with reference to the database and eliminated without the need to reject the whole sheet.
This increases the yield of usable product from the process and renders the whole process
more efficient.

The movable substantially flat screen copes well with the types of ink
(solid/liquid combinations) used in the printing of electrochemical sensors. The use of a
movable flat screen can enable better control of print definition and the deposition of the
thicker layers of ink needed in electrochemical sensors than may be allowed by rotogravure
or cylinder screen printing. A variety of types of screen (with different mesh, diameter of
thread in the mesh, thread separation, thickness, mesh count ) are readily commercially
available to cope with the different requirements of different types of ink in the continuous
web printing process (carbon, insulation, en2yme).

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Because of the arrangement of the flat screen, print roller, substrate and a
squeegee urging the screen towards the substrate, a variety of parameters are available to
be manipulated (screen to substrate angle, squeegee angle, screen to squeegee posmon,
sqneeg^toprMtouer position, snap distance, relative speeds of substrate and screen and
squeegee etc) to optimize the print process for electrochemical sensors.

To summarize briefly in a web manufacturing process for manufacturing
electrochemical sensors, the web expands or stretches as it is heated up and placed under
tension during the process. The printing stations (for example carbon, insulation, two
enzyme) typically each are followed by a drying station. In order to dry the inks efficrently
the drier stations operate at quitehigh temperatures (50-140 degrees centigrade).
Furthermore to aid registration of the web through each printing station, the web rs placed
under tension.

The substrate has to be kept under tension to control registration within the
process, as a result, whenever the substrate is heated for example to dry the inks after
printing, the substrate will stretch unpredictably causing image size variation in subsequent
prints.

The size of the image printed at each print station is determined by several
factors (stencil size, ink viscosity, relative web and stencil/screen speed and substrate
stretch at that point (both reversible and irreversible stretch) etcThe image size vanatron
(between different printing steps) when looked at the end of the process was found to vary.
It was unpredictable and higher than expected significantly reducing yields. If the
mismatch between image sizes between layers is greater than SOOmicrons along the web
(x-direction), the product will not work. The excessive hnage size variation was thought to
be due to excessive and unpredictable stretching (due to heating and tension) and shnnking
of the web substrate.

The problem of stretch and tension does not cause the same problems in flat bed
printing. Tosolvethe P roblemintheweb P rocess >P re-shrunksubstratewasrried. The

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substrate was heated to around 1 85 degrees centigrade before being used in the web
process. However, the variation in image size remained a problem, and caused reduced
yields.

The current proposal for the web process is the use of high temperatures in a
first drier or rather preconditioned at a sufficiently high temperature so that in one example,
irreversible stretch is substantially removed from the substrate, prior to an image being
printed on the substrate.

In a first processing station in the web machine, a drier bank heats the substrate
up to 1 60 degrees centigrade. The temperatures encountered by the substrate later in the
process, typically do not exceed 140 degrees.

In figure 2A the first heater bank that the unprinted substrate encounters is the
hot plate. This is a Teflon coated plate, which lifts and contacts the substrate during motion
of the web. The heat is introduced to the back face of the substrate. This is currently
running at a set point of 160°C with a specification of +A 4°C. The 160°C set point
statistically provided the best dimensional control. The calculated mean is 160.9°C. In
Bank 2 hot air is introduced to the front face of the substrate at a set point of 160°C with a
specification of +/- 4°C. The calculated mean is 1 61 .29°C. In Bank 3 hot air is introduced
to the front face of the substrate at a set point of 160°C with a specification of +/- 4°C. The
calculated mean is 161.18°C. In Bank 4 hot air is introduced to the front face of the
substrate at a set point of 160°C with a specification of +/- 4°C. The calculated mean is
160.70°C.

As a result of the web tension and the heat introduced in the drier, the web
substrate is stretched by approximately 0.7mm per artwork repeat. This was one of the
primary reasons for utilizing Station 1 as a preconditioning unit to stabilize the substrate
prior to subsequent printing stations. The use of Station 1 to precondition the substrate
improves the stability of Carbon and Insplarion Row Length since much of the material
stretch has been removed from the substrate prior to printing.

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In one embodiment of the present invention, high temperatures are used in a
first drier at a sufficiently high temperature so that irreversible stretch is substantially
removed from the substrate prior to any image being printed on the substrate (i.e. prior the
substrate reaching any print stations). In a first processing station in accordance with the
present invention, a drier bank heats the substrate to a first temperature which is
substantially higher than any temperature the substrate will encounter during the printing
process. For example, if the highest temperature the substrate will encounter during the
printing process is 1 40 degrees centigrade, the first temperature may be on the order of
approximately 160 degrees centigrade.

A method according to the present invention may be described by the following
steps. The steps including pre-conditioning a continuous substrate by heating to a first
temperature; printing an electrode layer on the substrate; exposing the electrode layer to a
heat source so that the electrode layer is heated to a second temperature; optionally, the
first temperature is greater than the second temperature. In further embodiments, the
method may also include the steps of printing an insulation layer on a continuous
substrate; exposing the insulation layer to a heat source so that the insulation layer is heated
to a third temperature wherein the the first temperature may be greater than the third
temperature.

In a further embodiment of the present invention, the substrate is pulled off a
roll at a predetermined tension and passed over a first heater bank which, in one
embodiment may be a Teflon coated hot plate. The hot plate lifts and heats the substrate as
it passes over the hot plate. Heat is thus introduced to the back face of the substrate. The
hot plate may be adjusted to heat the substrate to a temperature of approximately 1600C
+/- 5oC. The substrate then moves to a second heater bank where side of the substrate
opposite the hot plate is heated by hot air which has a temperature of approximately
1600C with a specification of +/- 5oC. The substrate then moves to a third heater bank
where side of the substrate opposite the hot plate is heated by hot air which has a
temperature of approximately 1600C +/- 5oC. The substrate then moves to a fourth heater

WO 2004/040285

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bank where side of the substrate opposite the hot plate is heated by hot air which has a
temperature of approximately 1600C +/- 5oC.

As a result of the web tension and the heat introduced in the drier, the web
substrate is preconditioned, thus reducing the stretching in subsequent process steps in a
continuous manufacturing process.

It will be recognized that equivalent structures may be substituted for the
structures illustrated and described herein and that the described embodiment of the
invention is not the only structure which may be employed to implement the claimed
invention, hi addition, it should be understood that every structure described above has a
function and such structure can be referred to as a means for performing that function.

While preferred embodiments of the present invention have been shown and
described herein, it will be obvious to those skilled in the art that such embodiments are
provided by way of example only. Numerous variations, changes, and substitutions will
now occur to those skilled in the art without departing from the invention. It should be
understood that various alternatives to the embodiments of the invention described herein
may be employed in practicing the invention. It is intended that the following claims
define the scope of the invention and that methods and structures within the scope of these
claims and their equivalents be covered thereby.

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CLAIMS

WHAT IS CLAIMED IS:

1 . A method of preconditioning a substrate in a web manufacturing process wherein said
web manufacturing process includes a plurality of printing steps, said method comprising
the steps of:

moving said substrate through said web process under tension;
heating said substrate as said substrate is passed through said printing steps,
wherein said substrate temperature does not exceed a first predetermined
temperature during said printing steps; and

passing said substrate into a preconditioning station wherein said substrate is heated
to a second predetermined temperature which exceeds said first predetermined
temperature.

2. A method according to Claim 1 wherein said second predetermined temperature is not
met or exceeded during subsequent stages of said web process.

3. A method according to Claim 2 wherein said second predetermined temperature i;
approximately 140°C.

4. A method according to Claim 2 wherein said preconditioning station includes at 1
one surface cleaning station adapted to remove impurities from said substrate.

5. A method according to Claim 2 wherein said first predetermined temperature is
approximately 1 60°C.

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6. A method according to Claim 1 wherein said substrate is stretched at a predetermined
tension prior to being heated to said second predetermined temperature.

7. A method according to Claim 6 wherein said predetermined tension is not exceeded
during subsequent stages of said web process.

8. A method according to Claim 7 wherein said second predetermined temperature is not
met or exceeded during subsequent stages of said web process.

9. A method according to Claim 8 wherein said preconditioning station includes at least
one surface cleaning station adapted to remove impurities from said substrate.

10. A method according to Claim 7 wherein said predetermined tension is approximately
165N and said second predetermined temperature is approximately 140°C.

1 1 . A method according to Claim 7 wherein said predetermined tension is approximately
165N and said first predetermined temperature is approximately 160°C.

12. A method according to Claim 1 wherein said second predetermined temperature is a
temperature sufficient to remove the irreversible stretch from said substrate.

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1/14

*£! o

ECT

O CO

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2/14

o
.8?
Q

CVJ

erf

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3/14

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6/14

FIG. 10

FIG. 11

FIG. 12

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7/14

FIG. 15 FIG. 16

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8/14

Top Left of Card Top Right of Card

FIG. 17A FIG. 17B

Bottom Left of Card Bottom Right of Card

FIG. 17C FIG. 170

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Top Left of Card

Top Right of Card

FIG. 18A

FIG. m

Bottom Left of Card

7700-f
1701-
242-

1703s]

FIG. 18C

Bottom Right of Card

242
242-

FIG. 18D

-1703

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Top Left of Card Top Right of Card

FIG. 19A FIG. 19B

Bottom Left of Card Bottom Right of Card

FIG.19C FIG.19D

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X Direction

(Print Direction)

FIG. 21 A

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f/G. 22

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Full text of "USPTO Patents Application 10560272"

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